1. Technical Field
The present invention pertains to medical item thermal treatment and/or monitoring systems, such as the types disclosed in U.S. Pat. No. 5,408,576 (Bishop); U.S. Pat. No. 6,259,067 (Faries, Jr. et al.); U.S. Pat. No. 6,294,762 (Faries, Jr. et al.); U.S. Pat. No. 6,371,121 (Faries, Jr. et al.); U.S. Pat. No. 6,384,380 (Faries, Jr., et al.); U.S. Pat. No. 6,376,805 (Faries, Jr. et al.); U.S. Pat. No. 6,467,953 (Faries, Jr. et al.); U.S. Pat. No. 6,566,631 (Faries, Jr. et al.) and U.S. Pat. No. 6,660,974 (Faries, Jr. et al.); U.S. Patent Application Publication Nos.: 2002/0147426 (Faries, Jr. et al.) and 2003/0114795 (Faries, Jr. et al.); and U.S. patent application Ser. No. 09/380,507, entitled “Method and Apparatus for Pressure Infusion and Temperature Control of Infused Liquids” and filed Apr. 24, 2000. The disclosures of the foregoing patents, patent publications and patent applications are incorporated herein by reference in their entireties. In particular, the present invention is directed toward monitoring intravenous solution or other medical items for compliance with prescribed requirements (e.g., manufacturer, medical standards or regulations, etc.) from the time the solution is prepared through disposal of the solution after use in a medical procedure. In other words, the medical solution or other medical items are monitored from manufacture at a manufacturing plant, through transport and/or storage to an end user or medical facility, through subsequent thermal treatment by that user and during administration to a patient. In this manner, a complete record of temperature and/or other conditions for the medical item is ascertained to determine and/or indicate to medical personnel compliance with the prescribed requirements.
2. Discussion of Related Art
Various types of medical items require heating to a selected temperature prior to utilization in a medical procedure. Generally, the medical items may be heated for limited time intervals to preserve their effectiveness. These items typically include intravenous solutions, irrigation fluids, surgical instruments, bottles and blankets. Intravenous (IV) fluids, for example, are typically stored in a cool environment and, consequently, require heating to precise temperatures to prevent thermal shock and injury from occurring during infusion of the fluid into a patient. Similarly, irrigation fluids can be warmed or cooled to various temperatures depending upon their intended use. These types of fluids are typically provided to a patient utilizing a flexible bag or container filled with the fluid and delivered via a fluid line that conveys the fluid from the bag to the patient.
Some medical items can only be heated for a limited period of time, or in accordance with controlled warming cycles, in order to avoid adversely affecting their effectiveness. For example, some fluids, such as whole blood or fluids containing medication, should be warmed evenly to a specific temperature and can be rendered unusable or unsafe if all or a portion of the fluid is overheated.
In order to provide the necessary heated items for use in medical procedures, the related art provides devices for regulating and/or monitoring temperature of medical items. For example, ovens may be disposed within operating rooms to heat items to desired temperatures. Further, U.S. Pat. No. 4,419,568 (Van Overloop) discloses a wet dressings heater having a base with side walls defining a cavity, and an insert connected to the base and defining at least one recess in the cavity for receiving wet dressings. A heater has an electrical heating element in close proximity to the insert recess for heating the wet dressings, while the temperature of the heating element is controlled in a desired temperature range for those wet dressings.
U.S. Pat. No. 4,495,402 (Burdick et al.) discloses a warmer for heating wet dressings and other articles disposed within a heating and storage compartment. The articles are arranged within the compartment in stacked relation and disposed on a plate that is supplied with thermal energy from a heater. The plate includes a center aperture whereby a first thermal sensor is disposed in the aperture in contact with a bottommost article. Control circuitry is disposed beneath the plate to control the heater to maintain temperature of the bottommost article at a desired level based on the temperatures sensed by the first thermal sensor and a second thermal sensor responsive to heater temperature.
U.S. Pat. No. 4,859,360 (Suzuki et al.) discloses a blood bag having a temperature-monitoring device in the form of a tag or label adhered to the bag outer surface. The temperature-monitoring device includes plural reversible temperature indicators each associated with a specific temperature range to indicate a current temperature of the blood, and an irreversible temperature indicator to indicate that the blood has currently or previously reached a predetermined temperature. The reversible indicators individually provide visual indications in response to the current blood temperature being within a corresponding range, while the irreversible indicator maintains a visual indication once the predetermined temperature has been reached.
U.S. Pat. No. 5,408,576 (Bishop) discloses an intravenous fluid warmer having a cabinet structure to accommodate a plurality of intravenous fluid bags. A temperature sensor and pad of heating filaments are disposed within the cabinet structure, whereby the temperature sensor enables automatic temperature regulation of the pad of heating filaments to heat the intravenous fluid bags. The heating filaments are covered by a rubber layer to prevent melting of the bags during heating. A temperature indicator disposed on the cabinet structure permits a user to ascertain when a desired temperature is attained, whereby an intravenous fluid bag is removed from the intravenous fluid warmer via an opening defined in a side of the cabinet structure.
U.S. Pat. No. 5,986,239 (Corrigan, III et al.) discloses a conductive warmer for flexible plastic bags. The warmer includes a heat-conducting member of thermally conductive material having a plurality of fins which are parallel and spaced apart to define a plurality of bag-receiving compartments. The fins are connected to a back portion of the heat-conducting member to which a heating element is attached in a heat-exchanging relationship. The heating element conducts heat through the back portion and fins of the heat-conducting member to the bags.
The devices described above suffer from several disadvantages. In particular, temperature and heating requirements are typically prescribed for medical solutions or other medical items from various sources (e.g., manufacturer, medical standard or regulation, etc.). These requirements typically prescribe a particular temperature range, expiration date or time and certain time intervals for heating the medical solution in order to maintain the solution efficacy. The above-described devices generally do not monitor medical items for or indicate compliance with these prescribed requirements throughout the life of the medical item (e.g., from manufacture through use and disposal). For example, the above-described warming devices may provide a temperature indication during heating, but do not monitor the heating time intervals for the medical items, the medical item temperatures during storage or usage outside of the device or the medical item expiration date. Although the Suzuki et al. device is secured to and monitors temperature of a blood bag, there is no manner for that device to monitor or indicate the heating intervals and/or passage of the expiration date or time for the blood bag. Thus, medical personnel may unknowingly administer to patients, solutions and/or medication that are unusable and/or have reduced potency due to non-compliance with prescribed requirements (e.g., an exceeded expiration date, prolonged exposure to heat, attainment of temperatures outside the prescribed range, etc.), thereby risking serious injury to patients.